82e9697250
If CONFIG_REFCOUNT_FULL=y, refcount_inc() WARN when refcount is 0. When creating a new btf, the initial btf->refcnt is 0 and triggered the following: [ 34.855452] refcount_t: increment on 0; use-after-free. [ 34.856252] WARNING: CPU: 6 PID: 1857 at lib/refcount.c:153 refcount_inc+0x26/0x30 .... [ 34.868809] Call Trace: [ 34.869168] btf_new_fd+0x1af6/0x24d0 [ 34.869645] ? btf_type_seq_show+0x200/0x200 [ 34.870212] ? lock_acquire+0x3b0/0x3b0 [ 34.870726] ? security_capable+0x54/0x90 [ 34.871247] __x64_sys_bpf+0x1b2/0x310 [ 34.871761] ? __ia32_sys_bpf+0x310/0x310 [ 34.872285] ? bad_area_access_error+0x310/0x310 [ 34.872894] do_syscall_64+0x95/0x3f0 This patch uses refcount_set() instead. Reported-by: Yonghong Song <yhs@fb.com> Tested-by: Yonghong Song <yhs@fb.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> |
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|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.